This invention relates to devices for leak testing of piping or tubing, and more particularly to a device for isolating an interior section of pipe or tubing to define a test section which can be subjected to pressure for the purpose of ascertaining the integrity of the section from the standpoint of leak tightness.
There are numerous instances in which sections of pipe or tubing are joined together and it is desired to check the connection to determine whether any leakage could occur. Among the fields in which such tubing is employed and in which fluid-tight interconnections between adjacent sections are desired is the oil and gas well drilling field. In that field, as the well bore is being drilled, various sections of tubing or pipe are lowered into the bore hole and connected to each other as the bore hole is drilled deeper. The pipe sections define a casing to prevent inward collapse of the bore hole and to permit withdrawal of the drilling fluids and debris, as well as to permit insertion and withdrawal of the drill head.
A number of devices have been developed in order to permit isolation of the piping section adjacent to a connection in order to define a restricted area within which a pressure test fluid can be introduced. Typically, such tools involve an elongated carrier member on which are positioned spaced packing rings which are expandable radially outwardly to contact the inner surfaces of the pipe on either side of the connection. The carriers on which the packing rings are positioned include passageways to permit the transmission of high pressure fluids from a pressure source to the space between the rings so that when the latter are expanded outwardly to define the axial limits of a test section, an enclosed volume is provided which includes the area to be tested as one surface thereof. Thus a pressurizable volume is provided to permit detection from the exterior of the pipe of any leakage which might take place at the area being tested.
Although a number of the prior art devices operate in a generally satisfactory manner, the slenderness and consequent flexibility of such devices results in high bending loads on the various tool sections during handling and use. A number of the prior art devices are prone to premature breakage or weakening because of stress cracks resulting from such loading conditions, and also from the high test pressures to which the devices are subjected, which can range from 5000 psi. to about 20,000 psi. It is therefore desirable to provide a pipe testing tool which is capable of quick and positive operation, and which can withstand high loading conditions to facilitate testing under high pressures while also being capable of withstanding the flexing loads to which such devices are oftentimes subjected in use.